Your Brain On: Depression

The disorder that tragically claimed Robin Williams's life has been around for millennia. The ancient Greeks thought depression started in the spleen. Later some blamed demonic possession for a person's lingering melancholy. Doctors today know better; depression begins and ends in your brain.

"Depression is a syndrome that likely emerges from several different brain processes that vary among patients," explains Boadie Dunlop, M.D., director of the Mood and Anxiety Disorder Program at Emory University. Put simply, no two brains are exactly the same, and the underlying causes of depression vary from person to person, Dunlop stresses.

That said, he and other modern-day mental health researchers have started to uncover some of the most common brain traits and conditions shared by depression sufferers.

The Emotion Connection

"Compared to people who are mentally well, patients with depression often show increases in activity in important emotion-processing regions," Dunlap says. Brain structures like the amygdala light up more vigorously among depressions sufferers, his research shows. Other studies have linked an uptick in amygdala activity to states of anger, sadness, and fear.

There's also research linking depression to the thalamus, a part of your brain that helps manage your responses to sensory information. The research hints that, among people with certain forms of depression, the thalamus might trigger their brains to produce unpleasant feelings in response to normal or benign external data, explains a report from Harvard Medical School. (Imagine a bummer feeling brought on by a sandwich, or a rerun of Grey's Anatomy.)

Beyond the Blues

People focus on emotions when talking about the blues. But your ability to think, learn, and memorize also suffer as a result of your depression. One recent study from Brigham Young University linked depression symptoms to a drop-off in a person's ability to store new information. No surprise since mental health experts have known for a while that depression can boost your brain's levels of stress hormones like cortisol, and studies have found that cortisol can damage or even shrink certain areas of your brain by stalling the production of new neurons and nerve connections.

In particular, an area of the brain called the hippocampus, which plays a big role in learning and long-term memory, was found to be 9 to 13 percent smaller among women with a history of depression in a study in The Journal of Neuroscience. A separate study from Swedish researchers found brain "plasticity," or your noodle's ability to change and adapt to new conditions and experiences, takes a hit as a result of long-term depression. All of this this could hurt your ability to learn and process new info, the study authors say.

The Long Term

Several research efforts have shown that people suffering from recurring depression develop problems with planning, decision-making, and setting priorities as well as continuing issues related to memory and learning. Those studies blame the neuron-growth-stunting, brain-structure-shrinking effects of stress chemicals related to the blues. More science has linked long-term depression to crippling brain conditions like dementia and Alzheimer's.

Drugs and/or therapy have been shown to help depression sufferers stall or overcome the negative effects of their condition. And Dunlop, the Emory depression expert, says new advancements in tracking the brain activity of sufferers could eventually help doctors better identify the best treatment programs for individual depression patients. But because of the syndrome's complexity, depression is-at least for now-something that can be treated, not cured.